1. Field of the Invention
The present invention relates to a multiple air hammer apparatus including a plurality of air hammers and its excavating direction correcting method.
2. Description of Related Art
A conventional multiple air hammer apparatus including a plurality of air hammers distributes the air supplied from one air supply line to each of the air hammers to activate it. Because of that, in the conventional air hammer apparatus, all the air hammers are simultaneously activated as the air is supplied from the air supply line, and are simultaneously stopped as the air supply is stopped.
The multiple air hammer apparatus with such construction has a problem in that: when one of the air hammers becomes a leaking state, the other air hammers cannot be sufficiently supplied with the air, so that the striking power becomes weakened, which leads to decreased excavation. To prevent this malfunction, very large amounts of air must be supplied to the multiple air hammer apparatus.
Japanese Patent Publication No. 3-45195 discloses a multiple air hammer apparatus that is provided with a function to correct an excavating direction. However, if the air hammer apparatus has such an excavating direction correcting function, the device is large and complex. Moreover, its correction operation takes considerable time.
The present invention has been developed in view of the above-described circumstances, and has as its object the provision of a multiple air hammer apparatus and its excavating direction correcting method which has a simple construction, which is energy efficient, and which can easily correct the excavating direction.
In order to achieve the above-described objects, the present invention is directed to a multiple air hammer apparatus in which a plurality of air hammers for striking bits mounted at a front end are disposed in a case and are activated by air supply, wherein: each of the plurality of air hammers is independently operatable.
According to the present invention, in a straight excavation, the earth is excavated by activating all the air hammers. In contrast, when correcting the excavating direction, only an air hammer which is positioned in the correct direction is activated first, and only the earth in the correct direction is excavated by striking and vibrating in a predetermined amount. Next, the earth is excavated by striking by rotating all the air hammers. Thereby, the air hammer apparatus progresses excavation toward the direction that the excavation is advanced, that is, the correct direction, and thus the excavating direction is corrected.
In order to achieve the above-described objects, the multiple air hammer apparatus is preferably characterized in that the bits are provided with an extending/contracting mechanism.
According to the present invention, in a case where the excavation progresses by building-in a casing at the same time as the excavation, the air hammer can be pulled out and be collected to the starting side by contracting a bit after the excavation has been carried out. Thereby, the excavation can be carried out regardless of existence and a size of the reached vertical shaft.
Moreover, in order to achieve the above-described object, the present invention is directed to an excavation direction correcting method of a multiple air hammer apparatus in which a plurality of air hammers for striking bits mounted at a front end are disposed in a case and are activated by air supply, wherein: a striking power of each of the bits is adjusted by separately controlling operation of one of the plurality of air hammers so as to correct an excavating direction.
According to the present invention, the excavating direction is corrected by, for example, activating only the air hammer that is positioned in a direction corresponding with the correct excavating direction and stopping the operations of all the other air hammers. Alternatively, the excavating direction is corrected by taking advantage of a difference in excavating speeds caused by differentiating the striking power of the air hammer that is positioned in the direction corresponding with the correct excavating direction.
In order to achieve the above-described objects, the present invention is directed to a swivel device which supplies fluid into each of a plurality of rotating supply pipes, the swivel device comprising: a case; a rotation body which is rotatably provided to the case, an end of the rotation body being connected with the plurality of supply pipes; a plurality of recesses which are formed at the rotation body with predetermined intervals and define supply chambers between the rotation body and the case; a plurality of supply passages which are formed at the rotation body and respectively connect the supply chambers and the supply pipes to each other; and a plurality of supply channels which are formed at the case with predetermined intervals and communicate with the case.
According to the present invention, the positions of the supply chambers are changed with the rotation of the rotation body, so that the supply channels connecting to each supply chamber are successively changed. Hence, if the fluid is supplied to only a particular supply channel, the fluid is supplied to only the supply chamber being connected to the particular supply channel, so that the fluid can be selectively supplied to the supply pipe that is being positioned to a particular direction. Thus, in an excavation apparatus provided with a plurality of excavation tools for example, the excavation direction can be corrected easily and efficiently.
In order to achieve the above-described objects, the present invention is directed to a multiple air hammer apparatus, comprising: a case; a rotation body which is rotatably provided to the case, an end of the rotation body being connected with a plurality of supply pipes; a plurality of recesses which are formed at the rotation body with predetermined intervals and define supply chambers between the rotation body and the case; a plurality of supply passages which are formed at the rotation body and respectively connect the supply chambers and the supply pipes to each other; and a plurality of supply channels which are formed at the case with predetermined intervals and communicate with the case, wherein activation air is supplied from an air supply device to each of the plurality of supply channels selectively so as to control activation of air hammers and correct an excavating direction.
According to the present invention, the activation air is supplied through all the supply channels in the straight excavation. The supplied activation air is supplied to the supply chambers that rotate and communicate with the supply channels, and is further supplied from the supply chamber to the air hammers via the supply passages and the supply pipes. Thereby, all the air hammers are activated and the earth is uniformly excavated to thus be excavated straight. In contrast, when correcting the excavating direction, for example, an air pressure of the activation air that is supplied to the supply channel positioned in the correct direction is set higher than an air pressure of the activation air that is supplied to the other supply channels, and the activation air is supplied. By this method, only the air hammer communicating with the supply channel at the correct direction can excavate the earth with a stronger striking power than the others; in consequence the entire air hammers gradually progress in the correct direction and thus the excavating direction is corrected. As described above, the excavating direction can be easily corrected by only controlling the supply operation of the activation air that is supplied to the air hammers.
In order to achieve the above-described objects, the present invention is directed to a multiple air hammer apparatus, comprising: a hammer case; a target provided on a central axis of the hammer case, the target being provided with a plurality of measurement points on a line from the center to a radial direction with predetermined intervals, wherein a deviation of the hammer case with respect to a planned design line is determined by determining positions of the plurality of measurement points with respect to the planned design line.
In order to achieve the above-described objects, the present invention is directed to a multiple air hammer apparatus, comprising: a hammer case; a plurality of air hammers which are housed and arranged in the hammer case and are activated by air supply so as to strike bits mounted at a front end; a rod which is coaxially connected with a back end of the hammer case; a plurality of supply pipes which are connected with the hammer case and supply activation air to the air hammers, respectively; and a swivel device which supplies the activation air from an air supply device to the plurality of supply pipes, wherein the multiple air hammer apparatus is arranged so as to be insertable into a casing.
In order to achieve the above-described objects, the present invention is directed to a rod which is connected with a multiple air hammer apparatus provided with a plurality of air hammers, supplies air to the multiple air hammer apparatus, and transmits rotation force and propulsive power to the multiple air hammer apparatus, the rod comprising: a main pipe which is hollow; a plurality of air supply pipes disposed around the main pipe, the plurality of air supply pipes respectively supplying the air to the air hammers; and connections which are formed at both ends of the main pipe and the plurality of air supply pipes.
According to the present invention, the air can be separately supplied to each of the air hammers from the plurality of air supply passages, which are disposed around the main pipe; thereby, each of the air hammers can be separately activated.
Preferably, the rod further comprises a water supply pipe arranged around the rod.
According to the present invention, water can be delivered because of the water supply pipe provided around the main pipe.
Preferably, the rod further comprises an auger wing arranged around the main pipe.
According to the present invention, the excavated soil can be efficiently discharged because of the auger wing around the main pipe.